1. Field of the Invention
The present invention relates generally to installing or running wellbore tubulars such as casing into a wellbore and, more particularly, to a modular handling tool system for holding and lowering the wellbore tubulars into the wellbore.
2. Description of the Background
A string of wellbore tubulars such as casing, depending on the length and type of tubular elements, may weigh hundreds of thousands of pounds. Despite this significant weight, the casing string must be carefully controlled as it is interconnected and lowered into the wellbore. To further complicate this function, wellbore tubulars, such as casing, come in a wide range of diameters and weights. In some cases, the casing may have a relatively thin wall that can be crushed if too much force is applied thereto.
Pneumatic and/or hydraulic casing tools are large gripping devices used for holding and lowering the wellbore tubulars, such as casing, into the previously drilled open hole. These gripping tools may weigh several tons depending on the size and type of slips used therein. The casing tools are typically used in sets comprising one elevator slip assembly and one spider slip assembly. The elevators slip assembly is translationally moveable with respect to the spider slip assembly. The elevator slip assembly is carried by the traveling block. The spider slip assembly may be a flush mount spider used on the drill floor with a rotary drive such as by replacing the master bushing. On the other hand, the spider assembly construction may need to provide a top mount spider that is mounted on the top of the rotary table or drill floor and which may be used with a scaffold or the like. Pneumatic and/or hydraulic control equipment is provided to operate the slips in the elevator slips assembly and in the spider assembly. Numerous pneumatic/hydraulic control lines are used to interconnect and operate the elevator slips assembly and the spider assembly.
To limit any downtime costs due to damage, maintenance, or repairs, it is generally desirable to provide on the rig site location backup or redundant gripping tools for both the elevator slip assembly and also for the type of spider slip assembly used. Thus, at least four tools are generally necessary at the rig site. The rental costs for having four large, rather complicated, tools on location can be substantial although such costs are preferable to the possibility of having one tool damaged without a spare on location. Due to the size and availability, considerable time may be needed to obtain a replacement. To save costs, it would be desirable to reduce such redundancy requirements while still maintaining the system reliability afforded by 100% redundancy.
Various prior art exists that is related to such gripping tools including U.S. Pat. No. 5,909,768, issued Jun. 8, 1999, to Castille et al., which discloses an exemplary apparatus for optimally gripping and releasing a tube. The apparatus has an elevator with a set of slips for optionally gripping and releasing a tube and a spider with a set of slips for optionally gripping and releasing the end of the tube. The elevator and spider slips are in communication with each other by pressurized conduits. The conduits form a pressure circuit to supply pressure to release one set of slips only when the other set of slips is gripping the tube, wherein the apparatus has improved response time. The spider may be hydraulically or pneumatically actuated and the elevator may be pneumatically operated. The spider may be flush mounted.
Other prior art patents may include U.S. Pat. Nos. 3,215,203; 3,708,020; 3,722,603; 4,676,312; 4,842,058, and 5,343,962.
The above referenced prior art does not disclose means for eliminating the need for having two backup tools at the rig site. It would be desirable to provide 100% redundancy for both the spider and the elevator without the need for two backup tools at the rig site. Eliminating even the fourth backup tool would clearly provide a significant 25% economy for both the vendor and the customer. Those skilled in the art have long sought and will appreciate the present invention which addresses these and other problems.
The present invention was designed to provide more efficient operation to thereby reduce drilling costs due to decreased equipment needs on location or in the provider""s warehouse. Manufacturing costs are reduced due to lower cost of building duplicate items rather than multiple items. Therefore, it is an object of the present invention to provide an improved handling system for holding and lowering wellbore tubulars, especially large tubulars such as casing, into the wellbore.
Another object of the present invention is to provide a handling system with 100% redundancy using fewer components.
Yet another object of the present invention is to provide a handling system with few different components.
Yet another object of the present invention is to reduce storage costs.
A feature of the present invention is a plurality of interchangeable gripping sections.
An advantage of the present invention is reduced operational and manufacturing and storage costs.
These and other objects, features, and advantages of the present invention will become apparent from the drawings, the descriptions given herein, and the appended claims. However, the invention is not limited to these objects, features, and advantages.
Therefore, the present invention provides for a handling system for holding and lowering wellbore tubulars for use with a rig having a traveling block and a rig floor. The system comprises at least two gripping modules that may preferably be substantially identical so as to be interchangeable with each other. The at least two gripping modules each have a bowl section and each have a plurality of slips moveable within the bowl section. An elevator adaptor is provided that has at least one connector for coupling to the traveling block. The elevator adapter is attachable with either one of the at least two gripping modules while another of the at least two gripping modules may be attachable to the rig floor. The elevator adaptor preferably defines a bore therein for receiving either one of the at least two gripping modules. The connector for the elevator module may further comprise lifting ears.
A third gripping module may preferably be provided for use in substituting with either of the at least two gripping modules so as to provide system redundancy.
A top mount module may be mountable to the rig floor and is attachable to either of the at least two gripping modules. The top mount body preferably defines a bore therein for receiving either of the at least two gripping modules.
The at least two gripping modules each preferably have a weight supporting shoulder or flange or ring extending radially outwardly for supporting a weight of the wellbore tubulars. The elevator adaptor has an engagement surface for contacting the weight supporting shoulder of either of the at least two gripping modules.
A plurality of slips is preferably longitudinally moveable within each of the at least two gripping modules. A sloping bottom surface within each of the at least two gripping modules is angled with respect to an axis through each of the at least two gripping modules. The sloping surface forms a stop surface for supporting and preventing further longitudinal movement of the plurality of slips toward a gripping position.
Thus, a plurality of rings are preferably within each of the at least two gripping modules. A plurality of slips are provided for each of the at least two gripping modules with each slip having substantially sawtooth set of camming surfaces for camming engagement with the plurality of rings.
A method is for a wellbore tubular handling system for installing wellbore tubulars in a wellbore. The method may preferably comprise providing at least two gripping modules for gripping wellbore tubulars, selecting either of the at least two gripping modules for attachment to the traveling block, and selecting either of the at least two gripping modules for attachment to the rig floor. In one preferred embodiment, the method comprises supplying at least three gripping modules at the rig for gripping wellbore tubulars such that the at least three gripping modules are interchangeable for attachment to either the traveling block or the rig floor. One of the at least three gripping modules provides redundancy for the other two of the at least thee gripping modules. The attachment to the traveling block further comprises providing an elevator module for interconnection between the traveling block and either of the at least two gripping modules.
In one example of operation, the attachment to the rig floor further comprises a top mount module for interconnection between the rig floor and either of the at least two gripping modules. However, the attachment to the rig floor could also comprise a flush mount adaptor ring for interconnection between the rig floor and either of the at least two gripping modules.
In operation, the method may typically comprise providing at least three gripping modules that are substantially identical so as to be interchangeable with each other, supplying the rig with the at least three gripping modules, and also supplying the rig with a tool for attaching any one of the three gripping modules for use with the traveling block.
Thus, one preferred embodiment of the handling system of the present invention comprises a plurality of identical or substantially identical gripping modules such that each of the plurality of gripping modules may be interchangeable with respect to each other. A first of the plurality of substantially identical gripping modules may be mountable to the traveling block. A second of the plurality of substantially identical gripping modules may be mounted such that the traveling block is translationally moveable with respect thereto for cooperation with the first of the plurality of substantially identical gripping modules in holding and lowering the wellbore tubulars. In one embodiment, an elevator/top mount module is provided that may be used either with the elevators or as a top mount module. Thus, the elevator/top mount module may be connectable to either the rig floor or to the traveling block. The elevator/top mount module may receive either the first or the second of the plurality of substantially identical gripping modules